<script setup lang="ts">
import { ref, watch } from 'vue'
import { useMouseInElement } from '@vueuse/core'
import { useTemplateRef } from 'vue'

 
const props = defineProps({
  mainPictures: {
    type: Array,
  } 
  
})
// 图片列表
 
// 1.小图显示大图
let bigImages = ref(0)
const handleClick = index => {
  bigImages.value = index
}
// 2.鼠标在元素内的位置
const target = useTemplateRef<HTMLDivElement>('target')

const { elementX, elementY, isOutside } = useMouseInElement(target)

// 这是滑块的位置。
let top = ref(0)
let left = ref(0)

let positionX = ref(0)
let positionY = ref(0)

watch([elementX, elementY,isOutside], () => {
  // 在里面是false，在外面是true
  if(isOutside.value){
    return  ;
  }
  if (elementX.value > 100 && elementX.value < 300) {
    left.value = elementX.value - 100
  }
  if (elementY.value > 100 && elementY.value < 300) {
    top.value = elementY.value - 100
  }
  if (elementX.value > 300) {
    left.value = 200
  }
  if (elementX.value < 100) {
    left.value = 0
  }
  if (elementY.value >= 300) {
    top.value = 200
  }
  if (elementY.value <= 100) {
    top.value = 0
  }
  positionX.value = -left.value * 2
  positionY.value = -top.value * 2
})
// 控制大图显示
</script>

<template>
  <div class="goods-image" v-if="mainPictures">
    <!-- 左侧大图-->

    <div class="middle" ref="target">
      <img :src="mainPictures[bigImages]">
      <!-- 蒙层小滑块 -->
      <div class="layer" :style="{left:`${left}px`,top:`${top}px`}">
      </div>
    </div>
    <!-- 小图列表 -->
    <ul class="small">
      <li v-for="(img, i) in props.mainPictures" :key="i" :class="{active: bigImages == i}" @mousemove="handleClick(i)">
        <img :src="img">
      </li>
    </ul>
    <!-- 放大镜大图 -->
    <div class="large" :style="[
        {
          backgroundImage: `url(${mainPictures[bigImages]})`,
          backgroundPositionX: `${  positionX    }px`,
          backgroundPositionY: `${  positionY      }px`
        }
      ]" v-show="!isOutside"></div>
  </div>
</template>

<style scoped lang="scss">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;

  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
  }

  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    z-index: 500;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    // 背景图:盒子的大小 = 2:1  将来控制背景图的移动来实现放大的效果查看 background-position
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }

  .layer {
    width: 200px;
    height: 200px;
    background: rgba(0, 0, 0, 0.2);
    // 绝对定位 然后跟随咱们鼠标控制left和top属性就可以让滑块移动起来
    left: 0;
    top: 0;
    position: absolute;
  }

  .small {
    width: 80px;
    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;

      &:hover,
      &.active {
        border: 2px solid $xtxColor;
      }
    }
  }
}
</style>
